This tip might not fix everyone's issue, but for the problem I was facing today this worked out just fine.
We have a scheduled weekly DTS package that is failing for the reason specified in this title: "Protocol error in TDS stream". For weeks we've just been running the thing manually, but that's not a solution, just a delay of the problem. I decided to investigate.
I found an article on the SQLTeam.com forums that helped get this working finally. For us, all that was necessary was to switch the database connection to ODBC over OLE DB. For some reason the OLE DB driver wasn't enjoying the network traffic from the stored procedure the package was calling, or that would be my best guess.
Anyways, score one for having one less thing to waste time on.
http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=95829